Combustion units (process furnaces, steam boilers and gas turbines) give rise to emissions of carbon dioxide, nitrogen oxides, sulphur dioxide and particulates. Nitrogen oxide emissions are most commonly reduced by combustion modifications that reduce temperatures and hence the formation of thermal NOx. The techniques include low NOx burners, flue gas recirculation, and reduced pre-heat. Nitrogen oxides can also be removed after they have formed by reduction to nitrogen using Selective Non Catalytic Reduction (SNCR) or Selective Catalytic Reduction (SCR). Water pollutant control. The main water pollutants from LVOC processes are mixtures of oil / organics, biodegradable organics, recalcitrant organics, volatile organics, heavy metals, acid / alkaline.
